It is well known that photographic processing solutions need to be replenished periodically in photographic processing apparatus to maintain constant sensitometry for the material being processed. Replenishment is made to the processing solutions so that their chemical composition and activity are kept within specified limits to maintain sensitometry for the material being processed.
The normal method of replenishment of photographic processing solutions in a continuous processor is to add liquids or solids to a processing tank and mix the replenisher into the tank solution by means of pumped recirculation. Replenishers must be at a higher concentration than the tank solution in order to make up for chemical usage by sensitized material which can be either paper or film.
In order to minimize both costs and waste there is a need to shorten process time and also to make more efficient use of the processing chemistry.